A great place to buy cheap and reliable Ink cartridges is either Costco or Office depot. I usually buy mine at Office depot because they supply a large variety of HP cartridges of all different colors.
One can find Lexmark 16 compatible ink cartridges at a good price from wholesale ink distributors such as 123 Inkjets and Inkjet Superstore. One can also find Lexmark 16 compatible ink cartridges at office supply stores, including Office Max and Staples.
You can find inkjet cartridges almost anywhere, Staples, Best Buy, Wal-Mart and Office Depot carry them. If you would like to purchase them online then I would suggest Amazon.
Vendors like InkjetSuperstore.com offer compatible inkjet cartridges at a good price. Another is 4inkjets.com. These sites specialize in ink, but you can also find it at TigerDirect.com.
Inkjet Printer Cartridges - Good sites. Atlascopy.com. The site is not all that user friendly but the prices are low and they have the best inkjet FAQ in the business.
You can find the least expensive ink cartridges for a large order at amazon. They have a lot of different sizes of cartridges there with a lot of good prices.
Law of Supply
To find an item like that for a good price, try scouting out local thrift stores for a good price, or a Walmart, Kmart, Christmas specialty store, or Target may all be suppliers.
You can buy cartridges for Canon at a variety of places whether online or in a retail store. For the best price I would try either Amazon or Overstock. If you are willing to take a chance EBay.
Toner cartridges can be found at ink world for a good price. You can compare with craigs list as well as e-bay on the toner web site will have good deals as well.
The price
One can find Hewlett-Packard inkjet cartridges to purchase on the Hewlett-Packard website. One can also find a good selection of cartridges on the Office Depot and Staples websites.
There are so many stores and online stores that you can check for getting cartridges for a good price and stores are like BestBuy, staples, Sam's, Costco, Wal-Mart etc.